erosion control-designated area
Legal term under Japan's Erosion Control Law; refers to areas where certain construction activities are regulated to prevent erosion and landslides.
Because this land is designated as an erosion control area, development requires permission.
砂防 is the broader concept of erosion control, while 砂防指定地 specifically refers to a legally designated area.
Compound of 砂防 (erosion control) + 指定地 (designated area).